In many electronic devices the display region includes a liquid crystal display (LCD) that is typically back lit to improve the visibility of the material displayed. For back lighting, a light guide is positioned behind the LCD to guide light to the whole surface. Light Emitting Diodes (LED) are generally positioned along a side of the light guide to deliver light across the whole of the LCD.
LCDs are sensitive and easily damaged so a protective layer is typically provided over the top of the display distanced by an air gap from the LCD to allow some give in the system if the front of the display receives a blow or is stressed or broken in some way.
The input region of an electronic device typically includes an array of keys used to input information. These keys will typically be provided on one or more key mats. It is sometimes desirable to illuminate the keys so that the device can be operated when ambient light is not sufficient. In these circumstances the legends associated with the keys are illuminated. These may be present on the keys themselves or on an opaque casing adjacent the associated key. In either instance a transparent light guide is generally provided behind the key mat to convey light to the legends.